<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    const properties = [
  "中华园,北京市,公寓",
  "华景苑,上海市,别墅",
  "新城市广场,深圳市,公寓",
  "雅居乐花园,广州市,别墅",
  "恒大城,广州市,公寓",
  "太阳花园,北京市,别墅"
];
const num1 = []
// properties.map(function(){
  for(let i = 0; i <  properties.length; i++){
 num1.push( properties[i].split(','))
  }
  console.log(num1);
const num2 = {}
num1.forEach(([num3, ,num4]) => {
if(num2[num4]){
  num2[num4].push(num3)
}else{
  num2[num4] = []
  num2[num4].push(num3)
}
})
console.log(num2);

// })








  </script>
</body>
</html>